Does a Greenfield Filter prevent or complicate an angiogram?

Question

Does a Greenfield Filter prevent or complicate an angiogram?

Answer 1

Excellent question. I assume you are talking about a cardiac cath or angiogram of the coronary vessels. A greenfield filter is placed in the vein, while the coronary angiogram involves the arteries. So no, they are basically unrelated.

HOWEVER, I assume the greenfield filter was placed for blood clots. You should also be on a blood thinner, which certainly causes problems with an angiogram. If you are not on blood thinners, it is likely because your bleeding risk was high. You will get a number of blood thinners administered to you during a coronary angiogram, so that will increase your risk of bleeding.

This is a complicated question to answer, I suggest you discuss your medical history with your doctor much in advance of your angiogram.

Answer 2

Physician Operators

All physician operators were radiologists or surgeons. The hospital is a private practice institution that has no operator credentialing requirements for filter placement. Each referring physician decided individually whether to refer patients to a radiologist or to a surgeon for filter placement. Other than cavography, no additional procedures were performed concurrently with filter placement when performed by surgeons.

Six radiologists placed filters. All radiologists were certified by the American Board of Radiology. Five of the six had subspecialty training in interventional radiology, certificates of added qualifications in vascular and interventional radiology, or both. These six radiologists placed between three and 42 filters each. Seven surgeons placed filters. One surgeon was certified by the American Osteopathic Association and certified in the subspecialty of thoracic surgery. The other six surgeons were certified by the American Board of Surgery. Of these six, two had subspecialty certification in vascular surgery and two in thoracic surgery. These seven surgeons placed between one and nine filters each.

Placement Analysis

Radiographs and cavograms were reviewed to evaluate filter position. When cavography was available, a correctly positioned filter was defined as being below the lowest of the renal veins in the inferior vena cava. In case of vena cava thrombosis, filter placement should be above the level of the thrombus. For each patient in whom cavography was not available, postprocedure radiographs were reviewed. In four of these patients, postprocedure CT scans obtained for other reasons were also available and were used to assess filter position. The radiographic criterion for correct positioning was defined as filter location between L1-L2 and L5. Because the renal veins typically join the inferior vena cava at L2 and the vena cava origin is typically at L5, these limits were thought to be reasonably sensitive and fairly specific in identifying misplacements. Very few placements evaluated with radiographs alone were borderline misplacements. Those that were, were not considered misplacements.

Complications

Procedure-related complications were recorded. Complications that required additional procedures or prolonged hospitalization or that resulted in death were considered major [2]. Follow-up was performed until hospital discharge.

Statistical Analysis

Statistical analysis of the data was performed using the chi-square and Student's t tests.

Results



Procedural data are shown in Table 2. One hundred forty-three filters were placed in 142 patients. A single filter was placed in each patient except the one patient who received a second filter after the first was misplaced in the right iliac vein by a surgeon (Fig. 1A,1B,1C). Radiologists placed 114 filters (80%) and surgeons placed 29 filters (20%). All filters were placed percutaneously with the patient under conscious sedation.

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